Page 443 - Review of Medical Microbiology and Immunology ( PDFDrive )

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mebooksfree.com mebooksfree.com mebooksfree.com 6. Regarding the patient in Question 5, which one of the following is mebooksfree.com
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PART VI Parasitology
432
SELF-ASSESSMENT QUESTIONS
(C) Giardia lamblia
(D) Trichomonas vaginalis
1. Regarding Entamoeba histolytica, which one of the following is
most accurate?
the best antibiotic to treat the infection?
(A) Entamoeba histolytica causes “flask-shaped” ulcerations in the
(A) Chloroquine
colon mucosa.
(B) Metronidazole
(B) Domestic animals such as dogs and cats are the main reservoir
(C) Nifurtimox
of E. histolytica.
(D) Praziquantel
(C) In the microscope, E. histolytica is recognized by having two
(E) Stibogluconate
sets of paired flagella. 7. Your patient is a 30-year-old Peace Corps volunteer who has
mebooksfree.com mebooksfree.com mebooksfree.com (A) Cryptosporidium hominis mebooksfree.com mebooksfree.com
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(D) Entamoeba histolytica infections are limited to the intestinal
recently returned from Central America. She now has fever and
mucosa and do not spread to other organs.
right-upper-quadrant pain. She reports that she had bloody diar-
(E) The infection is typically acquired by the ingestion of the tro-
rhea 2 months ago. A CT scan reveals a radiolucent area in the liver
phozoite in contaminated food and water.
that is interpreted to be an abscess. Aspiration of material from the
2. Regarding Giardia lamblia, which one of the following is most
abscess was performed. Microscopic examination revealed motile,
accurate?
nonflagellated trophozoites with ameboid movement. Of the fol-
(A) The drug of choice for giardiasis is chloroquine.
lowing, which one is the most likely cause of this infection?
(B) In giardiasis, ova and parasite (O&P) analysis of the stool
reveals sporozoites in the feces.
(B) Entamoeba histolytica
(C) Giardia lamblia produces an enterotoxin that increases cyclic
(C) Giardia lamblia
AMP within the enterocyte, resulting in diarrhea.
(D) Trichomonas vaginalis
(D) Giardia lamblia infection is acquired by ingestion of food or
water contaminated with human feces only (i.e., there is no
rhea for 2 weeks. He is HIV antibody positive with a CD4 count
animal reservoir for this organism). 8. Your patient is a 30-year-old man with persistent watery diar-
of 10. Routine stool culture revealed no bacterial pathogen. Ova
(E) Infection by G. lamblia occurs principally in the small intestine,
and parasite analysis revealed cysts that stained red in an acid-fast
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frequently resulting in the malabsorption of fat and foul-
stain. Of the following, which one is the most likely cause of this
smelling, frothy, fat-containing stools.
infection?
3. Regarding Cryptosporidium hominis, which one of the following is
(A) Cryptosporidium hominis
most accurate?
(B) Entamoeba histolytica
(A) Humans are the only reservoir for C. hominis.
(C) Giardia lamblia
(B) Microscopic examination of the diarrheal stool reveals both
(D) Trichomonas vaginalis
red cells and white cells.
(C) Laboratory diagnosis involves seeing cysts of the organism in
ANSWERS
an acid-fast stain of the stool.
(D) Cryptosporidium hominis is typically acquired by the ingestion
of trophozoites in contaminated food or water.
2. (E)
(E) In immunocompromised patients, such as AIDS patients with
a very low CD4 count, disseminated disease occurs that typi-
4. (A)
cally involves the brain and meninges. 1. (A)
5. (C)
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4. Regarding Trichomonas vaginalis, which one of the following is
6. (B)
most accurate?
7. (B)
(A) The drug of choice for trichomoniasis is metronidazole.
(B) Domestic animals, such as dogs and cats, are the principal res-
ervoir of the organism.
(C) Trichomonas vaginalis is typically acquired by contact with the
SUMMARIES OF ORGANISMS
cysts of the organism during sexual intercourse.
(D) Laboratory diagnosis typically involves the detection of a
Brief summaries of the organisms described in this chapter
greater than fourfold rise in the titer of IgA antibody.
begin on page 682. Please consult these summaries for a rapid
(E) The asymptomatic male sex partner of a woman with T. vaginalis
infection should not be treated because asymptomatic men are
rarely the source of the organism.
5. Your patient is a 30-year-old woman who returned from traveling
PRACTICE QUESTIONS: USMLE &
in Eastern Europe 1 week ago. While on the trip, she experienced review of the essential material.
COURSE EXAMINATIONS
anorexia, nausea but no vomiting, and abdominal bloating. For
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the last 2 days, she has had explosive watery diarrhea. An exami-
Questions on the topics discussed in this chapter can be found
nation of her stool revealed pear-shaped, flagellated, motile organ-
isms. Of the following, which one is the most likely cause of this
Board) Practice Questions starting on page 731. Also see Part
infection?
XIV: USMLE (National Board) Practice Examination starting
(A) Cryptosporidium hominis
on page 751.
(B) Entamoeba histolytica
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